proposed modifications to...

Proposed modifications to 100GBASE-DR Support for comments #120-126

1

Matt Traverso, Cisco Marco Mazzini, Cisco Hai-Feng Liu, Intel

version 0 IEEE 802.3cd Task Force , March 2017 Meeting

Supporters

• Brian Welch, Luxtera

• Gary Nicholl, Cisco

• Mike Dudek, Cavium

• Paul Kolesar, Commscope

• your name could be here…

2 version 0 IEEE 802.3cd Task Force , March 2017 Meeting

Background and Motivation

• The MPI (multi-path interference) penalty is a consequence of reflections within the channel medium. These reflections are expected to be challenging to measure and characterize in deployed networks

• In clause 124 (400GBASE-DR4), Table 124-13 describes the maximum number of discrete reflectances > -55 dB within the channel which the PMD can support

• The single column of reflectance tradeoffs in Table 124-13 is consistent with the expected deployed medium which consists of parallel fiber.

• Clause 140 (100GBASE-DR) which is defined over a duplex fiber pair is expected to be deployed over a mix of media – both parallel and duplex

• For example, see kolesar_3bs_01_0514, where a common fiber topology of a mixed duplex and parallel fiber is shown

• To support the heterogeneous environment of Clause 140, this presentation proposes to show impact of multiple magnitudes of reflectances

• Furthermore, we propose to tradeoff the MPI penalty with the supported channel loss

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Slide has no changes compared to traverso_022217_3cd_adhoc


http://www.ieee802.org/3/bs/public/14_05/kolesar_3bs_01_0514.pdf






Methodology Used 1) Reflectances:

Transmitter and Receiver are modeled to each have -26 dB reflectance Using combination of -35 dB reflectances & -45 dB reflectances in channel

• In the table these will be -35 dB to -45 dB reflectances and -45 dB to -55 dB reflectances respectively

Insert text stating that the effect of < -55dB reflectances may be ignored

2) MPI Calculation: Using king_02a_0116_smf spreadsheet for MPI calculation Using zero loss for connectors – pessimistic Using 3 dB in end-span insertion loss – as was done in Table 124-13 (400GBASE-DR4)

3) Link Budget Calculation: Channel insertion loss is 3 dB If MPI penalty is > 0.15 dB, then the penalty will be subtracted from 3.1 dB If MPI penalty is > 0.50 dB, the table will indicate that such channel is not supported

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http://www.ieee802.org/3/bs/public/adhoc/smf/16_01_07/king_02a_0116_smf.7z

Maximum Optical Return Loss • To determine the RIN parameter settings, it is important to specify the maximum optical return loss

• Below is a table capturing the return loss • Field addition with receiver, without loss in the channel

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Optical Return Loss (dB)

Number of discrete reflectances > -55 dB and -45 dB

0 1 2 3 4 5 6 7 8

Number of discrete reflectances

> -45 dB and -35 dB

0 25.08 24.24 23.48 22.78 22.13 21.53 20.97 20.44

1 23.36 22.67 22.03 21.44 20.88 20.35 19.86 19.39 18.95

2 21.34 20.79 20.27 19.78 19.32 18.88 18.46 18.06 17.68

3 19.70 19.24 18.81 18.39 18.00 17.62 17.25 16.90 16.57

4 18.33 17.93 17.56 17.19 16.85 16.51 16.19 15.88 15.59

5 17.14 16.79 16.46 16.14 15.84 15.54 15.25 14.97 14.70

6 16.09 15.79 15.49 15.20 14.93 14.66 14.40 14.15 13.90

Table is for reference – not to be included in standard

x.yz = these values either exceed the proposed MPI penalty limit or the number of connections exceeded the capability of the spreadsheet


MPI penalty

MPI Penalty (dB)


0 1 2 3 4 5 6 7 8


> -45 dB and -35 dB

0 0 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.10

1 0.05 0.06 0.05 0.09 0.11 0.12 0.11 0.15 0.12

2 0.1 0.12 0.13 0.16 0.19 0.2 0.22 0.23 0.22

3 0.18 0.18 0.2 0.2 0.24 0.3 0.3 0.32 *

4 0.26 0.27 0.32 0.34 0.36 0.4 0.41 * *

5 0.32 0.33 0.38 0.4 0.44 0.48 * * *

6 0.45 0.48 0.51 0.54 0.57 * * * *

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* = This combination of reflectances exceeds the number of connections supported in the Jonathan King spreadsheet, so were not calculated

For reference – not to be included in standard

x.yz = these values exceed the proposed MPI penalty limit – see slide 3


Proposed Addition of new table & supporting text

Channel Insertion Loss (dB)


0 1 2 3 4 5 6 7 8


> -45 dB and -35 dB

0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0

1 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0

2 3.0 3.0 3.0 2.9 2.9 2.9 2.9 2.9 2.9

3 2.9 2.9 2.9 2.9 2.9 2.8 2.8 2.8 *

4 2.8 2.8 2.8 2.8 2.7 2.7 2.7 * *

5 2.8 2.8 2.7 2.7 2.7 2.6 * * *

6 2.7 2.6 * * * * * * *

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* = This combination of reflectances is not supported

Insert text: Discrete reflectances below -55 dB may be ignored when determining supported channel insertion loss


Recommended Changes to Draft 1.2 (I)

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Change to -0.3 to align to DR4


Change to 15.5 dB Change to RIN15.5OMA




Recommended Changes to Draft 1.2 (II)

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Recommended Changes to Draft 1.2 (III)

10

Change to 5.6 dB to align to DR4

Change to “See 140.10.2.2” Change to -35 dB Change to “5.6 – max channel insertion loss per 140.10.2.2”

Add footnote for these parameters stating, higher penalties may be supported with reduced channel insertion loss. See 140.10.2.2



Recommended Changes to Draft 1.2 (IV)

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Update value to 27 dB

Change to “See 140.10.2.2”



Recommended Changes to Draft 1.2 (V) replace table 140-13 & add text

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Table 140-13 – Maximum channel insertion loss based on reflectances

* = This combination of reflectances is not supported

Channel Insertion Loss


0 1 2 3 4 5 6 7 8


> -45 dB and -35 dB

0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0

1 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0

2 3.0 3.0 3.0 2.9 2.9 2.9 2.9 2.9 2.9

3 2.9 2.9 2.9 2.9 2.9 2.8 2.8 2.8 *

4 2.8 2.8 2.8 2.8 2.7 2.7 2.7 * *

5 2.8 2.8 2.7 2.7 2.7 2.6 * * *

6 2.7 2.6 * * * * * * *

Insert text: Discrete reflectances below -55 dB may be ignored when determining supported channel insertion loss


Recommended Changes to Draft 1.2 (VI)

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Update to RIN15.5OMA

Add bullet to section 140.7.5 stating, - The optical return loss shall correspond to Table 140-6



Summary

• Proposed to use the total of link loss and MPI penalty in 100GBASE-DR link budget consideration, which would - resolve the debate on MPI penalty in the link budget, - support more channel usage cases, and - keep the same Tx OMA(min) and Rx sensitivity specifications as those in 400GBASE-DR4. - enable tradeoff of MPI penalty and channel insertion loss • Calculated optical return loss for 100GBASE-DR usage cases which gave 15.5 dB as the worst case ORL. • This supports comments (#119, 120, 121, 122, 123, 124, 125, 126) on D1.2 recommending that the editor adopt the remedies listed slides 8 through 13 in this presentation with editorial license


backup


400GBASE-DR4 Reference

DR4 array cord array cord array cable array cable array cord

DR4 400GBASE-DR4

500m Double link with 4 MPO connectors Connector Losses = 2.65 dB, Fiber loss = 0.25dB,

-> Link Loss = 2.9 dB (rounded to 3 dB)

MPI Penalty = 0.1 dB Agreed Budget = 3.1 dB

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this screenshot is from D2.2


Example: 4LCs + 3MPOs

0.93 0.93

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

0.00 1.00 2.00

cumulative probability

MPI penalty dB

PMD PMD

R 1 R 2 R 3 R 4 R 5 R 6 R 7 R 8 R 9 R 10 R 11 R 12

Rpmd RconF RconG RconG RconH RconK RconK RconH RconG RconG RconF Rpmd

Reflection level inputs-> -26 -35 -35 -35 -35 -45 -45 -45 -1000 -1000 -1000 -26

MPI Penalty = 0.34 dB


Example: 4LCs + 4 MPOs

1.02 1.02

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

0.00 1.00 2.00

cumulative probability

MPI penalty dB MPI Penalty = 0.36 dB

PMD PMD

R 1 R 2 R 3 R 4 R 5 R 6 R 7 R 8 R 9 R 10 R 11 R 12

Rpmd RconF RconG RconG RconH RconK RconK RconH RconG RconG RconF Rpmd

-26 -35 -35 -35 -35 -45 -45 -45 -45 -1000 -1000 -26


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